In this section, “Downtown Management District” means the district whose boundaries are set forth in Article II, § 61(a)(2)(i) of the Baltimore City Charter. Vacant and underutilized commercial buildings that are under a development plan are exempt from county property tax if: the real property is located in the Downtown Management District; the real property meets two of the following criteria: the improvement on the property is over 25 years old; the property was last used as commercial space with accessory uses; or the property has been at least 75% vacant for more than 3 years; the real property is owned by a person who: is engaged in constructing and operating housing structures or projects, including nondwelling commercial and community facilities; provides a minimum of $500,000 of private capital in the development of the residential portion of the project; renovates the real property so that at least 75% of the total leasable square footage of the building is used for rental residential housing; and demonstrates to the satisfaction of the Board of Estimates of Baltimore City the financial necessity for an agreement as authorized by this section; and the owner of the real property and the Baltimore City Board of Estimates agree on the payment that the owner shall make to Baltimore City in lieu of the county property taxes. Real property that qualifies for an exemption under this section is exempt from county property tax to the extent that the parties agree under subsection (b) of this section.